A known conveyor belt used in a conveyor belt device for transporting a target object to be conveyed includes a reinforcing layer including a plurality of steel cords aligned spaced apart from one another and a rubber layer that covers the reinforcing layer.
In manufacturing such a conveyor belt, the dimensions relating to the positions of the steel cords are required to be measured.
Examples of such dimensions include the cord pitch, i.e., the interval between steel cords, the distance between end cords, i.e., the interval between the steel cords positioned at both ends of the conveyor belt in the width direction, and the edge rubber width, i.e., the distance from the end surface of the conveyor belt in the width direction to the outer circumferential surface of the steel cord located adjacent to the end surface.
In the related art, the cross sections of the conveyor belt located at both ends of the conveyor belt in the longitudinal direction are measured by hand for these dimensions using calipers and/or a ruler after the conveyor belt is manufactured.
Thus, the dimensions at the intermediate portion of the conveyor belt in the longitudinal direction is unable to be measured during manufacture of the conveyor belt, and there is a demand for an enhancement in the measurement of dimensions of a conveyor belt.
Japan Unexamined Patent Publication No. 62-143252 describes a device configured to radiate X-rays at a rubber material embedded with steel cords, form a visual image from the transmitted X-rays on a fluorescent screen, image the visual image with a camera, and detect the arrangement of the steel cords.
Japan Unexamined Patent Publication No. 2015-81857 describes a device configured to radiate X-rays at a conveyor belt, detect the transmitted X-rays with a line sensor extending in the direction orthogonal to the extension direction of the steel cords, generate an X-ray transmission image, and obtain the thickness of the rubber layer on the basis of the luminance of the X-ray transmission image.
However, in the device of Japan Unexamined Patent Publication No. 62-143252, there is room for enhancement in ensuring measurement accuracy in imaging a visual image using a fluorescent screen.
Additionally, the device of Japan Unexamined Patent Publication No. 2015-81857 is configured to measure only the thickness of the rubber layer and not the dimensions relating to the positions of the steel cords, such as the cord pitch, the distance between end cords, and the edge rubber width.